CHAPTER 9 DVD ROM AND COMBO DRIVES

	Introduction :
	Digital Versatile Disk or Digital Video Disk (DVD) is a form of digital storage. DVD is used to stores music, video, games, and multimedia applications. The DVD is similar to the CD in appearance and structure. The DVD offers higher capacity and better quality as compared to the CD. The DVD storage capacity is seven times that of a CD. To play a DVD, a DVD ROM drive is used. In addition, combo drives are available that play DVDs as well as CDs.
9.1 Types of DVD
	The data on a DVD is arranged in a spiral manner. The data on the DVD is recorded outwards from the center.
	Spiral tracks on a DVD
	Each data track on the DVD is made up of millions of data pits. These data pits are incredibly tiny and are measured in nanometers. These pits are seen as bumps by the laser that is used to read the data.
	The basic composition of the DVD is made up of :
	_ Polycarbonate plastic - Forms the plastic layers. The plastic layers are arranged to form a spiral track. This spiral track is extremely long and has data encoded in it in the form of microscopic pits. _ Thin reflective layer - Covers the plastic layers. The reflective layers cover the surface of the disk. The inner layer is formed of aluminum and the outer of gold. _ Lacquer - All the layers of plastic are joined together with lacquer. The disk is then cured in infrared light. This completes the creation of the DVD, which is about 1.2 millimeters thick. DVDs can hold information on a single side or both sides. Double-sided DVDs contain data on both sides of the disk. The different types of DVDs are: _ Single-sided single-layered DVD - Known as DVD-5, as it has a capacity of 4.7 GB. Data is stored in a single layer on one side of the DVD. The capacity of this type of DVD is more than seven times the capacity of the CD. _ Single-sided dual-layered - Has a capacity of 8.5 GB It is also known as DVD-9. Data is stored on two layers on one side of the DVD. In this type of DVD, the laser has to read data from both the layers. The size of the data pits is increased from a single-sided single-layered DVD. Since the pits are larger in size, the number of pits in the spiral tracks reduces. As a result, data storage cannot be achieved to the maximum. Therefore, the single-sided duallayered DVD does not have double the capacity of the single-sided single-layered DVD. _ Double-sided single-layered - Known as DVD-10 and has a capacity of 9.4 GB. Data is storedin a single layer on both sides of a DVD. This type of DVD has to be reversed manually to play both sides. Some DVD players perform automatic reversal of the DVDs. _ Double-sided dual-layered - Has a capacity of 17 GB. This is over 26 times the data capacity of an ordinary CD. It is also known as DVD-18. This type of CD is very costly and is rarely used. It provides eight hours of audio or video playback. There are different types of DVDs available for different applications. The different types of DVDs are:
	9.1.1 DVD-ROM
	The DVD-ROM disk stores data ranging from 4.7 GB to 17 GB. DVD-ROMs store films, computer software in a similar manner to CD-ROMs.
	9.1.2 DVD-Video
	The DVD-Video disk stores movies. In this type of DVD, crater-like structures on the surface of the DVD scatter the laser beam. This is different from the way the laser is reflected in ordinary DVDs. These types of DVDs require DVD drives with MPEG-2 decoder.
	9.1.3 DVD-Audio
	DVD-Audio stores high-quality music. These disks can also store video content and slide shows. DVD-Audio holds the surround sound version of the music.
	9.1.4 DVD-Recordable (DVD-R) and DVD plus Recordable (DVD+R )
	The DVD-R and DVD+R disks can be written only once. An organic dye coats a layer of these types of disks. When the disk is exposed to laser, it is permanently marked. The data is read in a DVD player. DVD+R stores data in many layers on the disk. As a result, DVD+R can store more data than DVD-R. Hence, it is expensive.
	9.1.5 DVD-RW and DVD+RW
	The DVD-RW and DVD+RW disks are known as phase-change disks. These types of disks use two different laser power levels to write and erase data. We can rewrite DVD-RW disks about a thousand times. It is possible to rewrite DVD+RW disks around ten thousand times.
	9.1.6 DVD-RAM
	The DVD-RAMs use phase change technology. It is possible to rewrite these disks 1,00,000 times. DVD-RAM disks have a capacity of 9.4 GB, with 4.7 GB on each side of the disk. We do not need DVD burners to write data on these DVDs. These DVDs can be accessed in the same manner as a hard drive or floppy disk.
	9.1.7 DVD-VR and DVD+VR
	DVD-VR and DVD+VR disks can be used for the creation of movies that can be edited. The content in these disks can be edited by adding or removing portions and changing the required parts. DVDVR disks cannot be played on ordinary home DVD players. The DVD player has to be DVD-RW compatible. DVD+VR disks can be played on home DVD players.
9.2 DVD ROM Drives
	DVD ROM drives read DVDs of different types. These drives are read-only drives and cannot write or record information on a DVD. The speed of the DVD ROM drive is indicated by a number followed by an x. The x indicates the basic speed of the DVD-ROM drive, which is 11.08 Megabits per second. You can measure the speed of the DVD-ROM drive by multiplying 11.08 Megabits per second with the number that indicates the speed of the drive. DVD-ROM drives can have two to three speeds listed. An example of a DVD ROM speed listing is 4x/24x. The first speed refers to the maximum speed at which data is read from a DVD. For this drive, the maximum speed at which data is read from a DVD will be 11.08 x 4 = 44.32 Megabits per second. The second speed listing refers to the maximum speed at which data is read from a CD. The optional third speed listing refers to the CD ripping speed. This is the maximum speed at which data is read from an audio CD for conversion to a digital format.
9.3 Structure of the DVD ROM Drive
	The front of the DVD ROM drive has a tray that accepts the DVD. It has the Eject button that opens the tray. The Eject button is also used to close the DVD tray. The DVD ROM drive has a manual eject button. This button is used in cases of emergency, like the tray not opening. The volume control is also located on the front of the DVD drive. There is a port for connection for the microphone. There 196 is also a light that indicates the status of the DVD drive.
	Front Panel of the DVD Drive
	The back panel of the DVD players has different ports for the connection of the DVD drive to the computer. There is a digital audio connector. The Audio connector is the port that is connected to the sound card or motherboard of the computer. The jumper connections configure the DVD drive as either master or slave.
	Back Panel of the DVD Drive
	The IDE connection connects the DVD drive to the motherboard of the computer. The IDE cable makes this connection. IDE stands for Integrated Drive Electronics. The IDE interface provides an interface for storage devices such as the DVD drive. This interface integrates the controller to the data drives of the computer. The controller is a chip that controls the transfer of data between the computer and the DVD drive. The Power-in connector connects the power adapter to the DVD drive. It is a 4-pin connector. The drive is set to master if it is the only drive connected to the computer. If a DVD drive is already connected to the computer, the drive will be set to slave. The jumper connections have various options. These options are: _ CS - Stands for Cable Select. This option is never used. It is a reserved option. _ SL - Stands for Slave. It connects the DVD drive as a slave device. This is the default option. _ MA - Stands for Master. It connects the DVD drive as a master device. This option is selected when the DVD drive is the only one connected to the IDE cable.
	Jumper Selection on the DVD Drive
	The DVD ROM drive plays DVDs and CDs. The main components of the DVD drive are: _ Motor - Spins the disk in the drive. The motor performs rotations that move the disk in the drive. _ Laser - Reads the data in the disk. _ Lens - Focuses the laser beam on the precise location in the disk. _ Tracking mechanism - Moves the laser beam with micron accuracy.
9.4 Working of the DVD Drive
	The tracking system of the DVD player consists of the tracking motor and the spindle motor. It is responsible for the proper alignment of the data tracks on the DVD and the laser beam. The spindle motor spins the DVD at a rate that allows for constant reading of data by the laser beam. The tracking motor moves the laser assembly to and from the center of the DVD. The DVD drive reads data from DVDs with the help of a laser assembly, which focuses a laser beam on the DVD. The laser beam reads the data on the DVD that is stored in the form of microscopic pits. The laser beam focuses on the reflecting layer of the DVD. In the case of the single-layered DVDs, the laser passes through the layer and to the reflective layer underneath it. If the DVD is duallayered, it has to focus on the inner reflective layer by passing through the two layers and then to the reflective layer. The laser is reflected off the reflective layer onto an electronic device. The DVD track has data encoded in it in the form of pits, and the areas on the track that do not contain data are flat and smooth. The laser is reflected in a different manner from the smooth area as compared to the pits of data. The electronic device studies the reflected signal for changes in reflection. The device then interprets the reflection changes and reads them as bits of data. The DVD drive has to convert the data read from the DVD into understandable bits. These bits of data are then sent to a DAC (Digital to Analog Converter) if the data is intended for a device that uses analog data. If the device is digital, the data can be directly passed to the device.
9.5 Installing and Configuring the DVD Drive
	Installation of the DVD drive enables the user to view DVDs and CDs. If the DVD drive is an R, RW, or RAM drive, the user can also record information, movies and music on the DVD.
	Best practices
	1. Read the instructional manual of the DVD drive thoroughly. 2. Note down the model number and the product number of the DVD drive. 3. Check the front of the system case to ensure that an empty bay can accommodate the DVD drive.
	Precautions
	Wear an anti-static wristband.
	Hands on exercise
	To install the DVD drive : 1. Write down the details of the DVD drive, such as the model number, and the serial number. 2. Read the instruction manual of the DVD drive thoroughly. 3. Wear an anti-static wristband. 4. Shut down the computer and turn off the power switch at the back of the computer. For additional safety, remove the power cable.
	Removal of the Power Cable
	5. Remove the system case covering.
	Removal of the System Case Cover
	6. Remove the drive cover on the front of the system case.
	Removal of the System Case Cover
	7. Set the DVD drive as either master or slave. This setting depends on whether the IDE cable for the drive is attached to a device already. If the IDE cable is not attached to any device, the setting will be master. In the other case, it will be slave. The jumpers on the DVD drive enable the setting of the drive.
	Setting of the jumpers on the DVD drive
	8. If the system case uses rails to fit the DVD drive, fix the rails on the drive.
	Fixing of the rails on the DVD drive
	9. Put the DVD drive into the gap.
	Insertion of the DVD drive in the gap
	10. Use screws to fix the drive to the system case if there are no rails.
	Connection of the DVD Drive to the Computer
	11. Attach the CD-Audio cable of the computer to the connector of the DVD drive.
	The Connection of the CD-Audio Cable to the DVD Drive
	12. Attach the other end of the cable to the sound card or the motherboard.
	The connection of the CD-Audio Cable to the Motherboard
	13. Plug the IDE cable to the motherboard, if the DVD drive is a master. If the DVD drive is a slave device, the IDE cable will be connected to the motherboard.
	Connection of the IDE Cable to the Motherboard
	14. Connect the drive connector of the IDE cable to the DVD drive.
	Connection of the IDE Cable to the DVD Drive
	15. Connect the power adapter to the drive.
	Connection of the Power Adapter to the DVD Drive
	16. Replace the system case of the computer. 17. Replace the power cord of the computer and turn the power on. 18. In most cases, the DVD drive is automatically installed and configured by the computer when the computer is turned on. If it is not configured automatically, follow the steps in the instruction manual and configure the DVD drive accordingly.
	Hands on exercise
	To configure the DVD drive using the system BIOS : 1. Start the computer. 2. Press the Del key during the boot sequence to display the BIOS main menu. 3. Select Standard CMOS Setup using the navigation buttons specified on the screen. 4. Press Enter to display the Standard CMOS setup screen. 5. Verify that the DVD drive is set as the as the primary or secondary master/slave. 6. Save and Exit the BIOS setup.
9.6 Combo Drives
	In the early days of DVD, it was only possible to view DVDs with the use of DVD drives. This caused a lot of inconvenience to people who had to replace their functional CD drives with new DVD drives. This problem gave rise to the need for a new type of drive that would combine the functionality of DVD drives and CD drives. A combo drive is a CD writer drive that can play DVDs. This type of drive can play back DVD and CD. It can also write data in CD-R and CD-RW disks.
9.7 Troubleshooting the DVD Drive
	A user can experience many problems with the DVD drive. You have to manage the DVD drive properly in order to avoid occurrence of problems. In case a problem occurs, troubleshooting the drive will help to a great extent. Troubleshooting the DVD drive is very important, as a faulty drive can lead to damage of DVDs. This can cause loss of large amounts of data from a DVD.
	9.7.1 DVD Does Not Play
	The DVD inserted in the DVD drive is not playing. There can be many reasons for this problem. The DVD disk may be corrupted or it is possible that the drive is damaged. 1. Check the DVD for scratches on the surface. Also check if it is clean. If the DVD is unclean, use a soft linen cloth to clean it. Do not use circular motions. Clean from the center outwards in a radial manner. 2. Play another DVD in the drive. If this DVD is playing fine, it is possible that the drive is dirty. In this case, clean the DVD drive with a cleaning disk for DVD players. If the drive still does not play the disk after being cleaned, the drive is faulty. 3. Check if the cables of the DVD drive are connected properly. 4. Check if the operating system is recognizing the DVD drive. Go to My Computer and check if the drive is recognized. If this detail is not shown in My Computer, access the BIOS to check that the operating system is recognizing the drive. 5. The computer may not be working properly. Check the power supply fan. Also, ensure that the processor is not overheated. 6. It is possible that the Windows registry is corrupt. The registry is the database that contains configuration information of the computer. You can use utilities like the PC Bug Doctor to repair the faults in the Windows registry. This software utility can be downloaded from the site http:/ /www.pcbugdoctor.com/download.html. 7. If the above steps do not work, contact the manufacturer of the DVD drive.
	9.7.2 There is no Power in an External DVD Drive
	1. If the drive is an external drive, check the power cord. It should be plugged properly to the socket. Ensure that the cord is connected properly to the DVD drive as well. 2. If the connections are proper, connect another device to the socket. If the other device is playing, it means that the socket is fine. 3. Unplug the power cord a few times. Then try playing the DVD player. If the player does not play, the cord or the drive itself is faulty.
	9.7.3 There is no Power in an Internal DVD Drive
	1. The internal DVD drives receive power from the computer power supply. If the other parts of the computer are problem-free, it means the power supply is not at fault. 2. Replace the connector of the DVD drive to the power supply to check if the problem is cause by the connector. If the DVD drive does not start working even after the connector is replaced, the drive is faulty.
	9.7.4 The Tray of the Internal DVD Drive Will Not Open
	1. Restart the Computer. Then try to open the tray. 2. If the tray does not open after restarting, check the BIOS settings to see if the computer recognizes the drive. 3. Try the manual eject button on the DVD drive. 4. Shut down and unplug the computer. Use a small device like a paperclip to insert in the pinhole on the front of the DVD drive. Try to open the tray a little with the help of the paperclip, and then open with your fingers.